Spark-plug.



M. P. SULLIVAN.

SPARK PLUG.

APPLICATION FILED MAR. i, 1917.

1,281,429., Patented 0015.15, 1918;

//\/L/E/\ 717/? MAURICE I? SULLIVAN EA'URICE P, SULLIVAN, 015 NEW YGBK. N. 521, AESIG-NOR T5 SPEC AIMEE ELECTRZQAL' COMPANY, 03 NEWARK, NEW JERSEY.

sranK-rrine.

nestles.

Specification of Letters Patent.

UL n. a atented wet. to, redo.

To all whom it may concern:

Be it known that I, MAURICE l. SULLWAN, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in SparlePlugs, of which the following is a specification.

This invention relates to spark plugs and comprises means whereby high tension electric currents, generated by any suitable method are caused to produce in a highly efficient and desirable manner ignition sparks for the purpose of firing the explosive charges in the cylinders of internal combustion motors. I

One of the objects is to produce a plug in which the insulating member is protected from the severe heating influence of the exploding gases.-

Another object is the provision. of means to accommodate the discharge of the hot gases. and also means whereby the heat is readily conducted to the exterior parts of'the plug and there dissipated, rather than being concentrated on the interior with the result of unduly heating the central electrode and insulating element.

Another object is to obtain a plug which, together with the above qualities, is further characterized as one wherein the electrode terminals extend well into the region of the live cylinder gases, thereby giving a more certain and efltective action of the ignition spark.

These and other objects will become better understood after having pursued the follow ing description, together with the accompanying drawing which constitutes a part of this specification. With reference to said drawing, wherein like characters identify corresponding parts in each of the figures:

Figure a combined side elevation and longitudinal section of an assembled spark plug having embodied therein the features of my invention.

Fig. 2 is an end elevation of the plug looking as from the bottom.

Considering the drawing in particular 1 is the body or shell of the plug" constructed preferably of steel. Said shell terminates at one end in a nose portion 2 which for reasons to be explained hereinafter is of a comparative thick and heavy formation. The nose 2 is exteriorly threaded as at 3 to permit of its application to the orifice provided in the combustion cylinder. A shoulder at the unct1on of the nose 2 with the intermediate portion of the shell. and which maybe supplied with a gasket, serves to seat against the surface of the said cylinder to insure a leak-prooi joint. The upper end of said shell is preferably somewhat in cross-section than. the intermediate portion 1 and has it peripheral contour in the nature of a hexagon or other suitable shape in order to accommodate a Wrench for screwing the shell imposition. As seen in i this upper end is slotted at to any convenient depth thereby giving a series of fins integral with the body of the pin Said ins mav be of any desirable ruunber their object being to present a surface area. The shell 1 has an interior longitudinal recess '7 which extends to a point substaiu iallv opposite shoulder 4-. However it is not imperative that these parts he thus exactly related. Ere tending through the nose 2 to communicate with the recess 7 is a cylindrical recess which comprises the reduced section 8 and the still further reduced section 9. Said hollow section 9 has its lower. end provided with a circular groove into which a ring 10 is fitted. Ring 10 is made of round stock. preferably of a special alloy material, and serves as the distributed '2. to communicate with the interior of the plug independently of the central opening" 8, 9. l have illustrated four such passages 11 in the present embodiment. but it is of course apparent that any suitable number may be used. The uppermost end of the rccess 7 is provided with screw threads which receive a gland 12 sin'xilarly threaded as at 13 and engaging therewith tor the purpose of assemblingsaid gland into the body 1. Gland 12 carries a central electrode 14: insulated therefrom by a core of mica or other suitable n'laterial. and has its extremities projecting to a'considerable distance beyond either end of said gland. of this central electrode. when the gland is properly screwed in place. disposes itself concentrically within the ground electrode ring 10, 'coiiperating' therewith to give an infinitely large number of sparking points.

The lower end 1 the performance req Said ground electrode providing as does a large number of sparl zing points or made of round n'later-ial serves to out the accumulation of oil, carbon, and such art stances, With the result that the sparking terminals of the plug; are maintained clean and efiect-ive. The other end of central elem trode has a screw threaded portion 16 adapted to receive a nut 17 and thumb screw 18. A jacket 19 porcelain or the case of engines employed to drive automd hides. in the latter connection the speed and "Work are variable with seldom an occasion in which. the engine is called upon to exert its full capacity for any considerable duration of time. 'Iilut the conditions subjected to the aeroplane engine much more striugent, for here the engine is required to outlay its tullhorse power capacity at a substantially constant speed. At the present time these engines can only loo run a short While before it becomes necessary to overhaul and repair them, and experience shows that the spar: plug been a source of consiterable trouble and anuoyanc These conditions are due largely to the fact that the usual plug, even the recogoiried standards for automobile engines, are incapable of withstanding the severe heat subject-ed to them as a result Oil the continued peritormance of these aeroplane engines. Where p01? celain plugs are used the intenseheat generated frequently shatters the porcelain insulacor, or in the case of mica plugs the mica often flakes il and becomes suliiciently hot to causepreignition. l have tried out a large number of plugs and am aware th t various types and constructions have been used in this. class of service. lit is also co1nmon knowledge that many researchlaborer tories, including those of the l fted States Government, are constantly enucavoring to acquire means of constructing" plugs 'tl'iat will. stand up under the conditions above plained. But it is my heliet that the construction described and claimed herein is superior to anything heretol orc used.

Among the features of any "plug that enable me to acquire these ncc ssary ends is the heavy construction ot'ithe shell and the communicating passes therein. Tlhcsc orifices,

d beingextendiug from the recess 'l to the combustion cylinder of the engine afford an avenue whereby the major portion of the hot gases and combustion products may escape from the'interior of the plug" Without coming in contact with and unduly heating ortouling the central electrode. Also by furnishing a ready means of escape ofsaid gases the insulating core/15 is greatly relieved from their deteriorating action. In order to diminish much as expedient the exposure of the central electrode to the engine gases and at the same time to give additional stock to the nose 2, the opening 9 is made of a diameter suiiicientto suita lj/ &CCOXI1H1Gdat6 the electrode 10. The intermediate recess 8, bemade much smaller than recess 7, likewise in securing thick heavy walls for the nose portion 2, yet being of some what "larger diameter than opening 9 removes the liability of short circuit in the event of the presence of carbon or other foreign substances. The heavy walls of nose 52, secured as above explained, being of good heat conducting material serve to convey the heat upwardly and distribute it to the fins 6. Said line having a large surface area and being exposed to the air readily act to dissipate the heat as fast as it is conducted thereto. Furthermore the passages 11, located in the mass of the shell, furnish he; t conducting surfaces whereby much of the heat of the exploding gases is conducted directly to the shell and dissipated hy the fins 6. In this way the plug; is maintained cool, the heat of the exploding gases not loo ing permitted to accumulate, with injurious eli'ects in the region of the electrode and insulatingcore.

Another feature to be observed-is that the sparking terminals themselves are Well exposed to the live gases in the combustion cylinder in coutradistinction to numerous devices employing auxiliary combustion chambers which are apt to become stagnated by burnt gases.

1 am aware that the embodiment shown is susceptible to various modifications. For instance, While in the preferred form the recess passing through the nose 2 is made up of two stages 8 and 9, I may provide but one re having; the same diameter as said stage 8 and construct the ground electrode ring 10 accordingly to be supported therein in a manner similar to that shown. changes will also suggest themselves to those skilled in the art. However, it'is believed that such alterations are Within the spirit of the invention and scope of the annexed claims.

Having thus described my invention what ll claim is 2- 1. A. spark plug comprising a body memher reduced at one end and externally threaded for the purpose of attachment to 130 Other 12 nests-as a combustion cylinder, a series of cylindrical recesses of different sizes communicating with each other and arranged consecutively in the order of their diameters to extend throughout the length of said body, a thread cut in the recess at one end of said body and a circular ring arranged in the recess at the other end thereofto serve as a ground electrode, a gland engaged in said threaded recess, a central electrode arranged within said gland but spaced therefrom by means of an insulating core, said central electrode extending centrally through said series of.

recesses and cotiperating with the ground electrode ring,and a plurality of orifices passing through the said reduced portion of the body member to communicate with said threaded recess independently of the other of said recesses and serving as bypasses whereby the major portion of the gases collecting in said threaded recess may escape without coming in contact with the central electrode.

2. A spark plug comprising a body member having a reduced end threaded to its extremity for attachment with a combustion cylinder, said body member having an internally threaded recess at one end and a plain cylindrical recess in said' reduced portion but communicating with the first mentioned recess, a gland threaded into the first mentioned recess supporting an insulated central electrode'extending into the second mentioned recess and having a gasket member between the head of said gland and said body member, a ring seated in the lower -end of said second mentioned recess adjacent the end of said central electrode and serving as a coacting ground electrode, pass sages in the reduced end oi the body member extending from the first mentioned recess to the combustion cylinder at a point closely adjacent the spark gap wherebythe gases collecting in the first mentioned recess may escape independent of the second mentioned recess, said passages also serving as a means 3. A spark plug comprising a gland leaving an insulated central electrode, a body member having a longitudinal opening sue-- cessively reduced from one end of the body to the other end thereof, said gland supported in one end of said opening and a ground electrode ring supported in the other end, said central electrode being centrally located in said opening and extending to cotiperate with the ground electrode ring, said re duced opening serving to secure heavy walls for said body and a plurality of passages located in said walls to communicate with said opening, and heat dissipating fins on said body, said passages serving to lead the combustion products away from the central electrode and the walls of said body serving to conduct the heat to said fins, as described.

4. A spark plug comprising a body mean her having a heavy nose adapted for engage ment with a combustion cylinder, a recess within said body, a circular ring serving as a ground electrode formed and arranged in the end of said recess so as to prevent the accumulation of oils and combustion products, a central electrode located within said recess to coiiperate with the ground elec trode ring, a plurality of passages located Within said nose serving to conduct the combustion gases to and from said recess away from said central. electrode thereby preventing the latter from becoming unduly heated, said passages andhea y nose ing also to collect the heat said gases whereby the same is conducted to e1rterior of the body member, and means on exterior of the body member for dissipating said heat.

In witness whereof ll aiiix my signature.

MAURECE S LLKVAI L 

